This invention relates to an arrangement for mounting window glass sheet in an automotive door and more particularly to a retainer assembly for attaching the glass sheet to a liftplate movable within the door.
An example of a currently used mounting arrangement for automotive door glass sheet to a liftplate is shown in FIGS. 1-5 and denoted as prior art. The exploded perspective view in FIG. 1 shows a mounting arrangement comprising a T-nut or spanner nut retainer assembly 10', a spacer bushing 12', and a machine bolt 14' with a conical washer 15' for assembling a vehicle door glass sheet 16' to a liftplate 18'. As seen in FIG. 4 the T-nut retainer assembly 10' comprises a plastic capped retainer 20' and a metal T-nut 22' interlocked together. The capped retainer 20' is formed with a hollow stem portion 23' extending axially from a head portion 24' with the stem portion defining an axial bore 25' having a counter-bore 26'. The stem portion 23' is telescopically received in glass sheet circular hole 28'. The T-nut 22' has a hollow tubular portion 30' formed with an internal thread 32' for receiving the threaded shank 34' of the machine blot 14' after its insertion through liftplate aperture 36' and into the hollow stem 23'.
With reference to FIGS. 1 and 2 it will be seen that the stem portion 23' is formed with a pair of radial lugs 38' adapted for insertion in central opening 40' of the spacer bushing 12'. As seen in FIGS. 1-3 the spacer bushing opening 40' is formed with a pair of opposed cam ramps 42' while a radially extending lever arm 44' is provided on the bushing periphery. Thus upon the insertion of the stem 23' through the glass sheet hole 28' and its assembly within the spacer bushing opening 40' one-quarter counter clockwise turn of the lever arm 44' in the direction of arrow 46' (FIG. 1) locks the bushing 12' on the stem 23' and anchors the retainer in the glass sheet hole 28'. The glass sheet 28' is then fastened to the liftplate 18' by means of the machine bolt 14' being inserted through the liftplate aperture 36' the stem bore 25' and threaded into the T-nut stem internal threads 30'. One disadvantage of such a prior art fastener assembly is its lack of axial adjustment means between the spacer 12' and the retainer head portion 24' to compensate for dimensional variances in glass thickness or in the fastener components. This may result in a loose fit between the fastener assembly and the glass sheet causing the bushing 12' and retainer assembly 10' to slip and rotate as the bolt 14' is threaded into the T-nut.
The prior art solution to the above described slippage problem requires a pair of anti-rotation tabs 50' being lanced-out from the inner surface of the liftplate 18'. The tabs 50' provide stop edges 51' operative such that one of the edges is contacted by the bushing lever arm 44', as seen in FIG. 3. Thus, the lever arm 44', as positioned in dashed lines in FIG. 2, is adapted to be rotated in a clockwise direction (arrow 47') when the bolt 14' is turned in a threaded-on direction. It will be seen in FIGS. 2 and 3 that the lever arm 44' is adapted to be rotated a maximum of a few degrees than 180 degrees before it contacts lower stop edge 51' in FIG. 4 preventing further turning or slippage of the retainer assembly 10' and bushing 12' as the bolt 14' is being tightened.
It will be appreciated that the bushing surface must be flush with the opposed liftplate surface to allow one of the stop edges 51' to contact the lever arm 44'. Thus, if the bushing lever arm 44' overlies a tab 50' when positioning the glass sheet 16' the lever arm 44' will fail to contact the stop edge 51'. Further, such miss positioning of the lever arm 44' may cause a stress fracture of the glass sheet upon tightening of the bolt 14'.
The U.S. Pat. No. 3,282,013 issued Nov. 1, 1966 to J. H. Boicey discloses a mounting for glass including a clamping plate, which, in combination with a support plate, is adapted to mount a glass sheet therebetween in such a manner as to more uniformly distribute the securing pressure. The glass sheet and plates have aligned and longitudinally spaced bolt receiving openings. The clamping plate is provided on the surface facing the glass sheet with inwardly directed ridges adapted for bearing contact width a surface of the glass sheet, adjacent to but spaced from the openings whereby maximum clamping pressure is applied to the glass sheet at points remote from the openings.